JP5366434B2 - Fullerene derivative and organic photoelectric conversion device using the same - Google Patents

Description

  The present invention relates to a fullerene derivative and an organic photoelectric conversion element using the fullerene derivative.

Since fullerene derivatives are organic semiconductor materials having charge (electron, hole) transport properties, application to organic photoelectric conversion elements (organic solar cells, optical sensors, etc.) is expected. As a fullerene derivative as an organic semiconductor material, a fullerene derivative having 70 or more carbon atoms has attracted attention, and may be referred to as a [6,6] phenyl-butyric acid methyl ester derivative of C70 fullerene (hereinafter referred to as [70] PCBM). )It has been known. (Non-Patent Document 1)
Angew. Chem. Int. Ed. 2003, 42, 3371-3375

  However, when [70] -PCBM is used for the organic photoelectric conversion element, there is a problem that the photoelectric conversion efficiency is not always sufficient.

  Therefore, an object of the present invention is to provide a fullerene derivative having 70 or more carbon atoms that can provide excellent photoelectric conversion efficiency when used in an organic photoelectric conversion element.

（１）
[式（１）中、Ａ環は炭素数７０以上のフラーレン骨格を表す。Ｒ¹、Ｒ²およびＲ³は、それぞれ独立に、水素原子、ハロゲン原子、アルキル基、置換基を有していてもよいアリール基、置換基を有していてもよいアリールアルキル基、置換基を有していてもよい１価の複素環基または下記式（２）で示される基を表す。]

（２）
[式（２）中、ｍは１〜６の整数を、ｎは１〜４の整数を、ｐは０〜５の整数を表す。Ｘは、メチル基または置換基を有していてもよいアリール基を表す。ｍが複数個ある場合、複数のｍは同一でも異なっていてもよい。] The present invention first provides a fullerene derivative represented by the formula (1).

(1)
[In Formula (1), the A ring represents a fullerene skeleton having 70 or more carbon atoms. R ¹ , R ² and R ³ are each independently a hydrogen atom, a halogen atom, an alkyl group, an aryl group which may have a substituent, an arylalkyl group which may have a substituent, or a substituent. Represents a monovalent heterocyclic group which may have a group represented by the following formula (2). ]

(2)
[In Formula (2), m represents an integer of 1 to 6, n represents an integer of 1 to 4, and p represents an integer of 0 to 5. X represents a methyl group or an aryl group which may have a substituent. When there are a plurality of m, the plurality of m may be the same or different. ]

（３） （４）
（式（３）中のＲ¹およびＲ³、（４）中のＲ²は、それぞれ独立に、水素原子、ハロゲン原子、アルキル基、置換基を有していてもよいアリール基、置換基を有していてもよい１価の複素環基または式（２）で示される基を表す。） Secondly, the present invention provides a method for producing the fullerene derivative comprising reacting a fullerene having 70 or more carbon atoms with a glycine derivative represented by the formula (3) and an aldehyde compound represented by the formula (4).

(3) (4)
(R ¹ and R ^{3 in} formula (3), R ^{2 in} (4) each independently represents a hydrogen atom, a halogen atom, an alkyl group, an aryl group which may have a substituent, or a substituent. Represents a monovalent heterocyclic group which may have or a group represented by the formula (2).)

  Thirdly, the present invention provides a method for purifying a fullerene derivative represented by the formula (1), wherein the reaction product obtained by the above reaction is purified by silica gel column chromatography using an aromatic hydrocarbon and an acetate as a developing solvent. I will provide a.

  Fourthly, the present invention provides a composition comprising a fullerene derivative represented by the formula (1) and an electron donating compound.

  Fifthly, the present invention provides an organic photoelectric conversion device having a layer containing a fullerene derivative represented by the formula (1).

  Since the organic photoelectric conversion element which shows the outstanding photoelectric conversion efficiency can be manufactured if the C70 or more fullerene derivative of this invention is used, this invention is very useful industrially.

  Hereinafter, the present invention will be described in detail.

<Fullerene derivative>
The fullerene derivative of the present invention has a fullerene skeleton having 70 or more carbon atoms and is represented by the formula (1). In formula (1), R ¹ , R ² and R ³ each independently have a hydrogen atom, a halogen atom, an alkyl group, an aryl group which may have a substituent, or a substituent. An arylalkyl group, a monovalent heterocyclic group which may have a substituent, or a group represented by the following formula (2) is represented. The alkyl group usually has 1 to 20 carbon atoms, may be linear or branched, and may be a cycloalkyl group. Specific examples of the alkyl group include methyl group, ethyl group, n-propyl group, i-propyl group, n-butyl group, i-butyl group, t-butyl group, s-butyl group, 3-methylbutyl group, n -Pentyl group, n-hexyl group, 2-ethylhexyl group, n-heptyl group, n-octyl group, n-nonyl group, n-decyl group, n-lauryl group and the like. The hydrogen atom in the alkyl group may be substituted with a halogen atom, and examples thereof include a monohalomethyl group, a dihalomethyl group, a trihalomethyl group, and a pentahaloethyl group. Of the halogen atoms, it is preferably substituted with a fluorine atom. Examples of the alkyl group in which a hydrogen atom is substituted with a fluorine atom include a trifluoromethyl group, a pentafluoroethyl group, a perfluorobutyl group, a perfluorohexyl group, and a perfluorooctyl group.

The aryl group usually has 6 to 60 carbon atoms and may have a substituent. Examples of the substituent that the aryl group has include a linear or branched alkyl group having 1 to 20 carbon atoms, a cycloalkyl group having 1 to 20 carbon atoms, a linear or branched chain having 1 to 20 carbon atoms. Or an alkoxy group containing a C 1-20 cycloalkyl group in the structure thereof, or a group represented by the formula (2). Specific examples of the aryl group include a phenyl group, a C _{1 to} C ₁₂ alkoxyphenyl group (C _{1 to} C ₁₂ represents ₁ to ₁₂ carbon atoms, and the same applies to the following), C ₁ to C. ₁₂ alkylphenyl group, 1-naphthyl, 2-naphthyl and the like, preferably an aryl group having 6 to 20 carbon atoms, C ₁ -C ₁₂ alkoxyphenyl group, more preferably C ₁ -C ₁₂ alkylphenyl group . A hydrogen atom in the aryl group may be substituted with a halogen atom. Of the halogen atoms, it is preferably substituted with a fluorine atom.

The aforementioned C ₁ -C ₂₀ alkoxy group may be linear or branched, and may be a cycloalkyloxy group. Specific examples of the alkoxy group include methoxy group, ethoxy group, n-propyloxy group, i-propyloxy group, n-butoxy group, i-butoxy group, s-butoxy group, t-butoxy group, and n-pentyloxy. Group, n-hexyloxy group, cyclohexyloxy group, n-heptyloxy group, n-octyloxy group, 2-ethylhexyloxy group, n-nonyloxy group, n-decyloxy group, 3,7-dimethyloctyloxy group, n -Lauryloxy group etc. are mentioned. A hydrogen atom in the alkoxy group may be substituted with a halogen atom. Of the halogen atoms, it is preferably substituted with a fluorine atom. Examples of the alkoxy group in which a hydrogen atom is substituted with a fluorine atom include a trifluoromethoxy group, a pentafluoroethoxy group, a perfluorobutoxy group, a perfluorohexyl group, and a perfluorooctyl group.

The arylalkyl group usually has 7 to 60 carbon atoms and may have a substituent. As a substituent which the arylalkyl group has, a C1-C20 linear or branched alkyl group or a C1-C20 cycloalkyl group, a C1-C20 linear, branched And a group represented by the formula (2) include an alkoxy group having a C 1-20 cycloalkyl group in its structure. Specific examples of the aryl alkyl group, a phenyl -C ₁ -C ₁₂ alkyl group, C ₁ -C ₁₂ alkoxyphenyl -C ₁ -C ₁₂ alkyl group, C ₁ -C ₁₂ alkylphenyl -C ₁ -C ₁₂ alkyl group 1-naphthyl-C ₁ -C ₁₂ alkyl group, 2-naphthyl-C ₁ -C ₁₂ alkyl group and the like.

The monovalent heterocyclic group refers to the remaining atomic group obtained by removing one hydrogen atom from a heterocyclic compound. The carbon number of the monovalent heterocyclic group is usually about 4 to 60, preferably 4 to 20. The carbon number of the monovalent heterocyclic group does not include the carbon number of the substituent. The heterocyclic compound is an organic compound having a cyclic structure in which the elements constituting the ring include not only carbon atoms but also hetero atoms such as oxygen, sulfur, nitrogen, phosphorus, boron, silicon, etc. Say. As the monovalent heterocyclic group, an aromatic heterocyclic group is preferable. Specific examples of the monovalent heterocyclic group, a thienyl group, C ₁ -C ₁₂ alkyl thienyl group, a pyrrolyl group, a furyl group, a pyridyl group, C ₁ -C ₁₂ alkyl pyridyl group, piperidyl group, quinolyl group, isoquinolyl group etc., and a thienyl group, C ₁ -C ₁₂ alkyl thienyl group, a pyridyl group, a C ₁ -C ₁₂ alkyl pyridyl group are preferable.

  Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom. From the viewpoint of conversion efficiency when used in an organic photoelectric conversion element, a fluorine atom is preferable.

In the group represented by the formula (2), m represents an integer of 1 to 6, n represents an integer of 1 to 4, and p represents an integer of 0 to 5. When there are a plurality of m, the plurality of m may be the same or different. From the viewpoint of conversion efficiency when used in an organic photoelectric conversion element, m is preferably 2, n is preferably 2, and p is preferably 0. X represents a methyl group or an aryl group which may have a substituent. Specific examples of the aryl group which may have a substituent include the same groups as those described for R ¹ .

  Specific examples of the fullerene derivative represented by the formula (1) include compounds represented by the following formula.

（式中、Ａ環は前述と同じ意味を表す。）

(In the formula, ring A has the same meaning as described above.)

R ¹ in formula (1) is preferably a group represented by formula (2) from the viewpoint of photoelectric conversion efficiency when used in an organic photoelectric conversion element.

R ² and R ^{3 in} Formula (1) are aryl groups that R ² may have a substituent from the viewpoint of photoelectric conversion efficiency when used in an organic photoelectric conversion element, and R ³ is It is preferably a hydrogen atom.

  A ring in Formula (1) represents a fullerene skeleton having 70 or more carbon atoms. The carbon number of the fullerene skeleton (carbon cluster) is preferably 960 or less, more preferably 240 or less, and still more preferably 96 or less. In particular, a fullerene having 70 carbon atoms is preferable from the viewpoint of easy synthesis.

<Method for producing fullerene derivative>
The fullerene derivative of the present invention can be produced by reacting a fullerene having 70 or more carbon atoms, a glycine derivative represented by the formula (3) and an aldehyde compound represented by the formula (4). Specifically, an imine is generated by the reaction of a glycine derivative and an aldehyde compound, an iminium cation is generated by decarboxylation of the imine, and a 1,3-dipolar of the iminium cation and a fullerene having 70 or more carbon atoms A fullerene derivative is produced by a cycloaddition reaction (Prato reaction, Accounts of Chemical Research Vol.31 1998, pages 519-526).

  Examples of the glycine derivative represented by the formula (3) include N-methylglycine, N-octylglycine, N-phenylglycine, N-methoxymethylglycine, N- (2- (2-methoxyethoxy) ethyl) glycine and the like. Illustrated. The amount of the glycine derivative used in the reaction is usually 0.1 to 10 moles, preferably 0.5 to 3 moles per mole of fullerene having 70 or more carbon atoms.

  Examples of the aldehyde compound represented by the formula (4) include formaldehyde, acetaldehyde, propionaldehyde, benzaldehyde, naphthylaldehyde and the like. The amount of the aldehyde compound used in the reaction is usually 0.1 to 10 moles, preferably 0.5 to 4 moles per mole of fullerene having 70 or more carbon atoms.

  The above reaction is carried out in a solvent. As the solvent, a solvent inert to the reaction such as toluene, xylene, hexane, octane, chlorobenzene and the like is used. The amount of the solvent is usually 1 to 10,000 parts by weight with respect to 1 part by weight of fullerene having 70 or more carbon atoms.

  In the reaction, a fullerene derivative having 70 or more carbon atoms, a glycine derivative and an aldehyde compound may be mixed in a solvent and reacted by heating, and the reaction temperature is usually in the range of 50 to 350 ° C. The reaction time is usually 30 minutes to 50 hours. After the heating reaction, the reaction product is allowed to cool to room temperature, and the solvent is distilled off under reduced pressure using a rotary evaporator to obtain a reaction mixture.

The reaction mixture usually contains the fullerene derivative of the present invention, reaction by-products and unreacted raw materials. The reaction mixture can be separated and purified by silica gel column chromatography to obtain a fullerene derivative.
To obtain a high-purity fullerene derivative, carbon disulfide and acetate should be used as developing solvents for silica gel column chromatography, or aromatic hydrocarbons and acetate should be used as developing solvents for silica gel column chromatography. Aromatic hydrocarbons and acetates are more preferably used as developing solvents for silica gel column chromatography. In silica gel column chromatography, silica gel flash column chromatography is preferably used.

As the fullerene derivative obtained here, N-methylfulleropyrrolidine, N-ethylfulleropyrrolidine, N-methoxyethoxyethylfulleropyrrolidine, N-methoxyethoxyethylfulleropyrrolidine, N-ethyl-2- (1- And a fullerene derivative in which a group derived from a birimidine compound such as phenyl) fulleropyrrolidine and N-methoxyethoxyethyl-2- (1-naphthyl) fulleropyrrolidine and a fullerene having 70 or more carbon atoms are bonded.

<Organic photoelectric conversion element>
The organic photoelectric conversion element using the fullerene derivative of the present invention has a pair of electrodes, at least one of which is transparent or translucent, and a layer containing the fullerene derivative of the present invention between the electrodes. The fullerene derivative of the present invention can be used as an electron accepting compound or an electron donating compound, but is preferably used as an electron accepting compound. When the fullerene derivative of the present invention is used as an electron-accepting compound, the layer included in the organic photoelectric conversion element may be formed using only the fullerene derivative of the present invention, and the fullerene derivative of the present invention and the electron-donating compound are combined. You may form the layer contained in an organic photoelectric conversion element using the composition containing. The electron donating compound is preferably a polymer compound.

  Next, the operation mechanism of the organic photoelectric conversion element will be described. Light energy incident from a transparent or translucent electrode is absorbed by the electron-accepting compound and / or the electron-donating compound to generate excitons in which electrons and holes are combined. When the generated excitons move and reach the heterojunction interface where the electron-accepting compound and the electron-donating compound are adjacent to each other, electrons and holes are separated due to the difference in HOMO energy and LUMO energy at the interface. Electric charges (electrons and holes) that can move are generated. The generated charges can be taken out as electric energy (current) by moving to the electrodes.

As a specific example of the organic photoelectric conversion element using the fullerene derivative of the present invention,
1. A pair of electrodes, at least one of which is transparent or translucent, a first organic layer provided between the electrodes and containing the fullerene derivative of the present invention as an electron-accepting compound, and adjacent to the first organic layer An organic photoelectric conversion element having a second organic layer containing an electron donating compound provided;
2. An organic photoelectric conversion device having a pair of electrodes, at least one of which is transparent or translucent, and at least one organic layer provided between the electrodes and containing the fullerene derivative of the present invention and an electron-donating compound as an electron-accepting compound Characterized by that,
Either of these is preferable.

  From such a viewpoint, the organic photoelectric conversion element of the present invention has the above-described 2. Is preferred. In the organic photoelectric conversion element of the present invention, an additional layer may be provided between at least one electrode and the organic layer in the element. Examples of the additional layer include a charge transport layer that transports holes or electrons.

  In addition, 2. In the organic photoelectric conversion element, the ratio of the fullerene derivative in the organic layer containing the fullerene derivative and the electron donating compound of the present invention is preferably 10 to 1000 parts by weight with respect to 100 parts by weight of the electron donating compound. 50 to 500 parts by weight is more preferable.

  The organic layer containing the fullerene derivative of the present invention preferably includes an organic thin film containing the fullerene derivative. The thickness of the organic thin film is usually 1 nm to 100 μm, preferably 2 nm to 1000 nm, more preferably 5 nm to 500 nm, and further preferably 20 nm to 200 nm.

  The electron donating compound may be a low molecular compound or a high molecular compound. Examples of the low molecular weight compound include phthalocyanine, metal phthalocyanine, porphyrin, metal porphyrin, oligothiophene, tetracene, pentacene, and rubrene. Examples of the polymer compound include polyvinyl carbazole and derivatives thereof, polysilane and derivatives thereof, polysiloxane derivatives having an aromatic amine in the side chain or main chain, polyaniline and derivatives thereof, polythiophene and derivatives thereof, polypyrrole and derivatives thereof, polyphenylene vinylene and Examples thereof include polythienylene vinylene and derivatives thereof, polyfluorene and derivatives thereof, and the like. From the viewpoint of applicability, a polymer compound is preferable.

（５） （６）
[式（５）および（６）中、Ｒ⁴、Ｒ⁵、Ｒ⁶、Ｒ⁷、Ｒ⁸、Ｒ⁹、Ｒ¹⁰、Ｒ¹¹、Ｒ¹²およびＲ¹³は、それぞれ独立に、水素原子、アルキル基、アルコキシ基またはアリール基を表す。] From the viewpoint of the conversion efficiency of the organic photoelectric conversion element, the electron-donating compound used for the organic photoelectric conversion element is composed of a repeating unit represented by the following formula (5) and a repeating unit represented by the following formula (6). It is preferable that it is a high molecular compound which has a repeating unit chosen from, and it is more preferable that it is a high molecular compound which has a repeating unit represented by following formula (5).

(5) (6)
[In the formulas (5) and (6), R ⁴ , R ⁵ , R ⁶ , R ⁷ , R ⁸ , R ⁹ , R ¹⁰ , R ¹¹ , R ¹² and R ¹³ are each independently a hydrogen atom, alkyl Represents a group, an alkoxy group or an aryl group. ]

In the formula (5), specific examples in the case where R ⁴ and R ⁵ are alkyl groups include the same groups as those in the case of R ¹ described above. Specific examples of the case where R ⁴ and R ⁵ are aryl groups include the same groups as those for R ¹ described above.

The alkoxy group represented by R ⁴ and R ⁵ may be linear or branched, and may be a cycloalkyloxy group. Specific examples of the alkoxy group include methoxy group, ethoxy group, n-propyloxy group, i-propyloxy group, n-butoxy group, i-butoxy group, s-butoxy group, t-butoxy group, and n-pentyloxy. Group, n-hexyloxy group, cyclohexyloxy group, n-heptyloxy group, n-octyloxy group, 2-ethylhexyloxy group, n-nonyloxy group, n-decyloxy group, 3,7-dimethyloctyloxy group, n -Lauryloxy group etc. are mentioned. A hydrogen atom in the alkoxy group may be substituted with a halogen atom. Of the halogen atoms, it is preferably substituted with a fluorine atom. Examples of the alkoxy group in which a hydrogen atom is substituted with a fluorine atom include a trifluoromethoxy group, a pentafluoroethoxy group, a perfluorobutoxy group, a perfluorohexyl group, and a perfluorooctyl group.

In formula (5), from the viewpoint of the conversion efficiency of the organic photoelectric conversion element, at least one of R ⁴ and R ⁵ is preferably an alkyl group having 1 to 20 carbon atoms, and an alkyl group having 4 to 8 carbon atoms. It is more preferable that

In the above formula (6), specific examples in the case where R ^{6 to} R ¹³ are alkyl groups include the same groups as those in the case of R ¹ described above. Specific examples of the case where R ^{6 to} R ¹³ are alkoxy groups include the same groups as those described above for R ⁴ . Specific examples of the case where R ^{6 to} R ¹³ are aryl groups include the same groups as those for R ¹ described above.

In the formula (6), R ^{8 to} R ¹³ are preferably hydrogen atoms from the viewpoint of ease of monomer synthesis. From the viewpoint of conversion efficiency when used in an organic photoelectric conversion element, R ⁶ and R ⁷ are preferably an alkyl group having 1 to 20 carbon atoms or an aryl group having 6 to 20 carbon atoms, and 5 carbon atoms. It is more preferably an alkyl group of ˜8 or an aryl group of 6 to 15 carbon atoms.

（７） Specific examples of the polymer compound used as the electron-donating compound include a polymer compound composed of a repeating unit represented by the formula (7).

(7)

  The organic photoelectric conversion element of the present invention is usually formed on a substrate. This substrate may be any substrate that does not change when an electrode is formed and an organic layer is formed. Examples of the material for the substrate include glass, plastic, polymer film, and silicon. In the case of an opaque substrate, the opposite electrode (that is, the electrode far from the substrate) is preferably transparent or translucent.

  Examples of the transparent or translucent electrode material include a conductive metal oxide film and a translucent metal thin film. Specifically, indium oxide, zinc oxide, tin oxide, and a composite film thereof (NESA) manufactured using a conductive material made of indium / tin / oxide (ITO), indium / zinc / oxide, or the like. Etc.), gold, platinum, silver, copper and the like are used, and ITO, indium / zinc / oxide, and tin oxide are preferable. Examples of the method for producing the electrode include a vacuum deposition method, a sputtering method, an ion plating method, a plating method, and the like. Moreover, you may use organic transparent conductive films, such as polyaniline and its derivative (s), polythiophene, and its derivative (s) as an electrode material. Furthermore, as the electrode material, a metal, a conductive polymer, or the like can be used. Preferably, one of the pair of electrodes is preferably a material having a small work function. For example, metals such as lithium, sodium, potassium, rubidium, cesium, magnesium, calcium, strontium, barium, aluminum, scandium, vanadium, zinc, yttrium, indium, cerium, samarium, europium, terbium, ytterbium, and two of them One or more alloys, or one or more of them and an alloy of one or more of gold, silver, platinum, copper, manganese, titanium, cobalt, nickel, tungsten, tin, graphite, or a graphite intercalation compound are used. It is done. Examples of the alloy include magnesium-silver alloy, magnesium-indium alloy, magnesium-aluminum alloy, indium-silver alloy, lithium-aluminum alloy, lithium-magnesium alloy, lithium-indium alloy, calcium-aluminum alloy and the like.

  As a material used as a buffer layer as an additional layer, an alkali metal such as lithium fluoride, a halide of an alkaline earth metal, an oxide, or the like can be used. In addition, fine particles of an inorganic semiconductor such as titanium oxide can be used.

<Method for producing organic thin film>
The method for producing the organic thin film is not particularly limited, and examples thereof include a method by film formation from a solution containing the fullerene derivative of the present invention.

  Solvents used for film formation from solution include hydrocarbon solvents such as toluene, xylene, mesitylene, tetralin, decalin, bicyclohexyl, n-butylbenzene, sec-butylbenzene, t-butylbenzene, carbon tetrachloride, chloroform, Halogenated saturated hydrocarbon solvents such as dichloromethane, dichloroethane, chlorobutane, bromobutane, chloropentane, bromopentane, chlorohexane, bromohexane, chlorocyclohexane and bromocyclohexane, and halogenated unsaturated hydrocarbons such as chlorobenzene, dichlorobenzene and trichlorobenzene And ether solvents such as tetrahydrofuran, tetrahydropyran and the like. The fullerene derivative can usually be dissolved in the solvent in an amount of 0.1% by weight or more.

  The solution may further contain a polymer compound. Specific examples of the solvent used in the solution include the above-mentioned solvents. From the viewpoint of the solubility of the polymer compound, a hydrocarbon solvent is preferable, and toluene, xylene, and mesitylene are more preferable.

  For film formation from solution, spin coating method, casting method, micro gravure coating method, gravure coating method, bar coating method, roll coating method, wire bar coating method, dip coating method, spray coating method, screen printing method, flexographic method Coating methods such as a printing method, an offset printing method, an ink jet printing method, a dispenser printing method, a nozzle coating method, a capillary coating method can be used, and a spin coating method, a flexographic printing method, an ink jet printing method, and a dispenser printing method are preferable.

  By irradiating light such as sunlight from a transparent or translucent electrode, the organic photoelectric conversion element generates a photovoltaic force between the electrodes and can be operated as an organic thin film solar cell. It can also be used as an organic thin film solar cell module by integrating a plurality of organic thin film solar cells.

  In addition, by applying light from a transparent or translucent electrode in a state where a voltage is applied between the electrodes, a photocurrent flows and it can be operated as an organic photosensor. It can also be used as an organic image sensor by integrating a plurality of organic photosensors.

  Examples will be shown below for illustrating the present invention in more detail, but the present invention is not limited to these examples.

As reagents and solvents used in the synthesis, commercially available products were used as they were, or products purified by distillation in the presence of a desiccant. The NMR spectrum was measured using MH500 manufactured by JEOL, and tetramethylsilane (TMS) was used as an internal standard. The infrared absorption spectrum was measured using FT-IR 8000 manufactured by Shimadzu Corporation. The MALDI-TOF MS spectrum was measured using BRUKER AutoFLEX-T2.

Step 1: Dean-Stark トラップを装着した2口フラスコにブロモ酢酸 (20.8 g, 150 mmol)、ベンジルアルコール(16.2 g, 150 mmol)、パラートルエンスルホン酸 (258 mg, 1.5 mmol)、ベンゼン (300 mL)を加え120 ℃ で 24 時間脱水縮合した。溶媒をエバポレーターで減圧留去し、ついでシリカゲルフラッシュカラムクロマトグラフィー (展開溶媒：ヘキサン/エチルアセテート=10/1, 5/1)で精製してブロモ酢酸ベンジルエステル(34.3 g, 150 mmol) を黄色油状物として定量的に得た。: R_f 0.71 (hexane/ethyl acetate=4/1); ¹H NMR (500 MHz, ppm, CDCl₃, J=Hz) δ 3.81 (s, 2H), 5.14 (s, 2H), 7.31 (s, 5H); ¹³C NMR (125 MHz, ppm, CDCl₃) δ 25.74, 67.79, 128.27, 128.48, 128.54, 134.88, 166.91; IR (neat, cm^-1) 2959, 1751, 1458, 1412, 1377, 1167, 972, 750, 698. Synthesis of benzyl (2- (2-hydroxyethoxy) ethylamino) acetate

Step 1: In a two-necked flask equipped with a Dean-Stark trap, bromoacetic acid (20.8 g, 150 mmol), benzyl alcohol (16.2 g, 150 mmol), para-toluenesulfonic acid (258 mg, 1.5 mmol), benzene (300 mL) ) Was added and subjected to dehydration condensation at 120 ° C for 24 hours. The solvent was distilled off under reduced pressure with an evaporator, and then purified by silica gel flash column chromatography (developing solvent: hexane / ethyl acetate = 10/1, 5/1) to give bromoacetic acid benzyl ester (34.3 g, 150 mmol) as a yellow oil It was obtained quantitatively as a product. : R _f 0.71 (hexane / ethyl acetate = 4/1); ¹ H NMR (500 MHz, ppm, CDCl ₃ , J = Hz) δ 3.81 (s, 2H), 5.14 (s, 2H), 7.31 (s, 5C); ¹³ C NMR (125 MHz, ppm, CDCl ₃ ) δ 25.74, 67.79, 128.27, 128.48, 128.54, 134.88, 166.91; IR (neat, cm ^-1 ) 2959, 1751, 1458, 1412, 1377, 1167, 972, 750, 698.

Step 2: Triethylamine (17 mL, 120 mmol) was added to a solution of bromoacetic acid benzyl ester (13.7 g, 60 mmol) in dichloromethane (90 mL) at 0 ° C under an argon atmosphere, and the resulting mixture was added at the same temperature for 20 min. Then, a solution of 2- (2-aminoethoxy) ethanol (12 mL, 120 mmol) in dichloromethane (40 mL) was added, and the mixture was stirred at room temperature for 4 hours. Next, the organic layer was washed with water (3 times), dried over anhydrous magnesium sulfate, the solvent was distilled off under reduced pressure with an evaporator, and silica gel flash column chromatography (developing solvent: ethyl acetate / methanol = 1/0, 10/1, 5/1) Purification gave glycine ester 2 (12.2 g, 48.0 mmol) in 80% yield as a colorless oil. : R _f 0.48 (ethyl acetate / methanol = 2/1); ¹ H NMR (500 MHz, ppm, CDCl ₃ , J = Hz) δ 2.83 (t, 2H, J = 5.1 Hz), 3.50 (s, 2H) , 3.52 (t, 2H, J = 4.6 Hz), 3.58 (t, 2H, J = 5.0 Hz), 3.65 (t, 2H, J = 4.6 Hz), 5.11 (s, 2H), 7.28-7.30 (m, 5H); ¹³ C NMR (125 MHz, ppm, CDCl ₃ ) δ 48.46, 50.25, 61.29, 66.38, 69.80, 72.23, 126.63, 128.12, 128.37, 135.30, 171.78; IR (neat, cm ^-1 ) 3412, 2880, 1719, 1638, 1560, 1508, 1458, 1067, 669.

Step 1: アルゴン雰囲気下ベンジル２−（２−（２−ヒドロキシエトキシ）エチルアミノ）アセテート（２） (6.58 g, 26 mmol) のジクロロメタン (50 mL) 溶液にトリエチルアミン (4.3 mL, 31 mmol)を０℃で加え、ついで４−（N,N-ジメチルアミノ）ピリジン (DMAP) (32 mg, 0.26 mmol) を加え、得られた混合液を20分攪拌後、これにジ-ｔｅｒｔ-ブチルジカルボネート (6.77 g, 31 mmol) のジクロロメタン(10 mL)溶液を滴下した。反応混合液を室温で4時間攪拌後、水を入れた３角フラスコ中に注ぎ入れて反応を停止しジエチルエーテル抽出（3回）を行った。有機層を乾燥後、減圧濃縮、ついでシリカゲルフラッシュカラムクロマトグラフィー (展開溶媒：ヘキサン/酢酸エチル= 3/1, 2.5/1, 2/1) 精製を行い、ベンジル｛tert-ブトキシカルボニル−［２−（２−ヒドロキシ−エトキシ）エチル］アミノ｝アセテート(5.83 g, 16.5 mmol) を収率 63 % で無色油状物として得た。: R_f 0.58 (エチルアセテート/メタノール=20/1); ¹H NMR (500 MHz, ppm, CDCl₃, J=Hz) δ 1.34 (d, 9H, J= 54.5 Hz), 2.19 (brs, 1H), 3.38-3.45 (m, 4H), 3.50-3.60 (m, 4H), 3.99 (d, 2H, J= 41.3 Hz), 5.09 (d, 2H, J= 4.1 Hz), 7.25-7.30 (m, 5H); ¹³C NMR (125 MHz, ppm, CDCl₃) δ 27.82, 28.05, 47.90, 48.20, 49.81, 50.39, 61.23, 66.42, 69.92, 72.12, 80.08, 127.93, 128.14, 135.25, 154.99, 155.19, 169.94, 170.07; IR (neat, cm^-1) 3449, 2934, 2872, 1751, 1701, 1458, 1400, 1367, 1252, 1143; Anal. Calcd for C₁₈H₂₇NO₆: C, 61.17; H, 7.70; N, 3.96. Found: C, 60.01; H, 7.75; N, 4.13. Synthesis of (2- (2-methoxyethoxy) ethylamino) acetic acid (1)

Step 1: Triethylamine (4.3 mL, 31 mmol) was added to a solution of benzyl 2- (2- (2-hydroxyethoxy) ethylamino) acetate (2) (6.58 g, 26 mmol) in dichloromethane (50 mL) under an argon atmosphere. Then, 4- (N, N-dimethylamino) pyridine (DMAP) (32 mg, 0.26 mmol) was added, and the resulting mixture was stirred for 20 minutes, after which di-tert-butyl dicarbonate ( 6.77 g, 31 mmol) in dichloromethane (10 mL) was added dropwise. The reaction mixture was stirred at room temperature for 4 hours, poured into a triangular flask containing water, the reaction was stopped, and diethyl ether extraction (three times) was performed. The organic layer was dried, concentrated under reduced pressure, and then purified by silica gel flash column chromatography (developing solvent: hexane / ethyl acetate = 3/1, 2.5 / 1, 2/1) to obtain benzyl {tert-butoxycarbonyl- [2- (2-Hydroxy-ethoxy) ethyl] amino} acetate (5.83 g, 16.5 mmol) was obtained as a colorless oil in a yield of 63%. : R _f 0.58 (ethyl acetate / methanol = 20/1); ¹ H NMR (500 MHz, ppm, CDCl ₃ , J = Hz) δ 1.34 (d, 9H, J = 54.5 Hz), 2.19 (brs, 1H) , 3.38-3.45 (m, 4H), 3.50-3.60 (m, 4H), 3.99 (d, 2H, J = 41.3 Hz), 5.09 (d, 2H, J = 4.1 Hz), 7.25-7.30 (m, 5H ); ¹³ C NMR (125 MHz, ppm, CDCl ₃ ) δ 27.82, 28.05, 47.90, 48.20, 49.81, 50.39, 61.23, 66.42, 69.92, 72.12, 80.08, 127.93, 128.14, 135.25, 154.99, 155.19, 169.94, 170.07 ; IR (neat, cm ^-1 ) 3449, 2934, 2872, 1751, 1701, 1458, 1400, 1367, 1252, 1143; Anal.Calcd for C ₁₈ H ₂₇ NO ₆ : C, 61.17; H, 7.70; N, 3.96.Found: C, 60.01; H, 7.75; N, 4.13.

Step 2: Under a argon gas atmosphere, sodium hydride (1.2 g, 24.8 mmol, 50% in meneral oil) in tetrahydrofuran (THF) (10 mL) solution in benzyl {tert-butoxycarbonyl- [2- (2-hydroxy- Ethoxy) ethyl] amino} acetate (5.83 g, 16.5 mmol) in THF (20 mL) was added dropwise at 0 ° C., and the mixture was stirred at the same temperature for 20 min, and then iodomethane (1.6 mL, 24.8 mmol) was added at 0 ° C. . The reaction mixture was stirred at room temperature for 20 hours, and then the reaction was stopped by adding water while cooling with an ice bath. Extracted with ether (3 times), dried organic layer, concentrated under reduced pressure, purified by silica gel flash column chromatography (developing solvent: hexane / ethyl acetate = 5/1, 3/1) and purified by benzyl {tert-butoxycarbonyl- [ 2- (2-Methoxy-ethoxy) ethyl] amino} acetate (3.02 g, 8.21 mmol) was obtained as a colorless oil in a yield of 50%. : R _f 0.54 (hexane / ethyl acetate = 1/1); ¹ H NMR (500 MHz, ppm, CDCl ₃ , J = Hz) δ 1.34 (d, 9H, J = 51.8 Hz), 3.28 (d, 3H, J = 2.7 Hz), 3.37-3.46 (m, 6H), 3.52 (dt, 2H, J = 5.4Hz, 16.5 Hz), 4.02 (d, 2H, J = 34.8 Hz), 5.09 (d, 2H, J = 4.5 Hz), 7.24-7.30 (m, 5H); ¹³ C NMR (125 MHz, ppm, CDCl ₃ ) δ 24.93, 25.16, 44.68, 45.00, 46.70, 47.40, 55.78, 63.30, 67.22, 68.60, 76.95, 124.98, 125.14, 125.36, 132.49, 151.99, 152.31, 166.84, 166.96; IR (neat, cm ^-1 ) 2880, 1751, 1701, 1560, 1458, 1400, 1366, 1117, 698, 617; Anal.Calcd for C ₁₉ H ₂₉ NO ₆ : C, 62.11; H, 7.96; N, 3.81. Found: C, 62.15; H, 8.16; N, 3.83.

Step 3: Trifluoroacetic acid (TFA) in a solution of benzyl {tert-butoxycarbonyl- [2- (2-methoxy-ethoxy) ethyl] amino} acetate (3.02 g, 8.21 mmol) in dichloromethane (17 mL) under argon atmosphere (9.0 mL) was added and stirred at room temperature for 7 hours. Subsequently, 10% aqueous sodium carbonate solution was added to adjust the pH to 10, followed by extraction with dichloromethane. The organic layer was dried over anhydrous magnesium sulfate, concentrated under reduced pressure, and benzyl [2- (2-methoxy-ethoxy) ethylamino] acetate (2.18 g). , 8.19 mmol) was obtained quantitatively as a yellow oil. : R _f 0.32 (ethyl acetate / methanol = 20/1); ¹ H NMR (500 MHz, ppm, CDCl ₃ , J = Hz) δ 1.99 (brs, 1H), 2.83 (t, 2H, J = 5.3 Hz) , 3.38 (s, 3H), 3.50 (s, 2H), 3.54 (t, 2H, J = 4.6 Hz), 3.60-3.62 (m, 4H), 5.17 (s, 2H), 7.32-7.38 (m, 5H ); ¹³ C NMR (125 MHz, ppm, CDCl ₃ ) δ 48.46, 50.66, 58.76, 66.20, 70.00, 70.44, 71.64, 128.09, 128.33, 135.44, 171.84; IR (neat, cm ^-1 ) 3350, 2876, 1736 , 1560, 1458, 1117, 1030, 698, 619; Anal.Calcd for C ₁₄ H ₂₁ NO ₄ : C, 62.90; H, 7.92; N, 5.24. Found: C, 62.28; H, 8.20; N, 5.05.

Step 4: Activated carbon (219 mg) supported on 10% by weight of palladium on a solution of benzyl [2- (2-methoxy-ethoxy) ethylamino] acetate (2.19 g, 8.19 mmol) in methanol (27 mL) at room temperature. In addition, after purging with hydrogen gas, the mixture was stirred for 7 hours at room temperature in a hydrogen atmosphere. Pd / C was removed with a glass filter with a celite pad, the celite layer was washed with methanol, and the filtrate was concentrated under reduced pressure. [2- (2-Methoxyethoxy) ethylamino] acetic acid (1) (1.38 g, 7.78 mmol ) Was obtained as a yellow oil in 95% yield. : ¹ H NMR (500 MHz, ppm, MeOD, J = Hz) δ 3.21 (t, 2H, J = 5.1 Hz), 3.38 (s, 3H), 3.51 (s, 2H), 3.57 (t, 2H, J = 4.4 Hz), 3.65 (t, 2H, J = 4.6 Hz), 3.73 (t, 2H, J = 5.1 Hz); ¹³ C NMR (125 MHz, ppm, MeOD) δ 48.13, 50.49, 59.16, 67.08, 71.05 , 72.85, 171.10; IR (neat, cm ^-1 ) 3414, 2827, 1751, 1630, 1369, 1111, 1028, 851, 799; Anal.Calcd for C ₇ H ₁₅ NO ₄ : C, 47.45; H, 8.53; N, 7.90. Found: C, 46.20; H, 8.49; N, 7.43.

Example 1 (Synthesis of fullerene derivative 1)
In a three-necked flask equipped with a Dimroth condenser, C ₇₀ (manufactured by Frontier Carbon) (100 mg, 0.12 mmol), glycine derivative 1 (32 mg, 0.18 mmol), and 1-naphthaldehyde (37 mg, 0.24 mmol), Chlorobenzene (30 mL) was mixed and refluxed by heating at 150 ° C. for 1 hour under an argon atmosphere. The mixture is allowed to cool to room temperature, the solvent is distilled off under reduced pressure using a rotary evaporator, and the resulting solid is separated and purified by silica gel flash column chromatography (developing solvent: carbon disulfide / ethyl acetate = 1/0 to 20/1). The desired fullerene derivative (Compound 4) (68 mg, 0.06 mmol, yield 51%) was obtained. This fullerene derivative is referred to as fullerene derivative 1.
Rf 0.3 (toluene only); IR (KBr) 2874, 1427, 1132, 1103, 795, 752 cm ⁻¹ .
MALDI-TOF-MS (matrix: SA) found 1111.428 (calcd for C ₈₇ H ₂₁ NO ₂ , exact mass: 1111.16).

Example 2 (Production and Evaluation of Organic Thin Film Solar Cell)
Regioregular poly-3-hexylthiophene (manufactured by Aldrich, lot number: 01004AH, Mw = 43000, Mn = 22000) as an electron donor was dissolved in o-dichlorobenzene at a concentration of 1% (weight%). Thereafter, the mixture of regioisomers of fullerene derivative 1 was mixed into the solution as an equal weight electron acceptor with respect to the weight of the electron donor. Subsequently, it filtered with the Teflon (trademark) filter with the hole diameter of 1.0 micrometer, and produced the application | coating solution.

A glass substrate provided with an ITO film with a thickness of 150 nm by a sputtering method was subjected to surface treatment by ozone UV treatment. Next, the coating solution was applied by spin coating to obtain an active layer (film thickness of about 100 nm) of the organic thin film solar cell. Thereafter, baking was performed in a vacuum at 90 ° C. for 60 minutes. Then, lithium fluoride was vapor-deposited with a thickness of 4 nm by a vacuum vapor deposition machine, and then Al was vapor-deposited with a thickness of 100 nm. The degree of vacuum at the time of vapor deposition was 1 to 9 × 10 ⁻³ Pa in all cases. Moreover, the shape of the obtained organic thin-film solar cell was a regular square of 2 mm × 2 mm. The photoelectric conversion efficiency of the obtained organic thin-film solar cells is generated by irradiating a certain amount of light using a solar simulator (product name: OTENTO-SUNII: AM1.5G filter, irradiance: 100 mW / cm ² ). The current and voltage were measured and determined. The results are shown in Table 1.

Comparative Example 1 (Production and Evaluation of Organic Thin Film Solar Cell)
An organic thin film solar cell was prepared in the same manner as in Example 2 except that [70] PCBM was used instead of the fullerene derivative 1, and the photoelectric conversion efficiency was determined. The results are shown in Table 1. [70] The product name ADS71BFA (manufactured by American Dice Source, lot number: 07L022E) was used as [70] PCBM.

Example 3 (Synthesis of fullerene derivative 2)
Under an argon atmosphere, a three-necked flask equipped with a Dimroth condenser was charged with C ₇₀ (Aldrich) (194 mg, 0.23 mmol), glycine derivative 1 (80 mg, 0.45 mmol), and 1-naphthaldehyde (0.1 g, 0.64 mmol). Toluene (500 mL) was mixed and heated to reflux for 10 hours. The mixture is allowed to cool to room temperature, the solvent is distilled off under reduced pressure using a rotary evaporator, and the resulting solid is separated and purified by silica gel flash column chromatography (developing solvent: carbon disulfide / ethyl acetate = 1/0 to 95/5). The obtained crystals were recrystallized from a toluene / methanol mixed solvent to obtain the desired fullerene derivative (compound 5) (54 mg, 21%) as a mixture of regioisomers (brown powder, TLC: Rf = 0.52 ( toluene)). This fullerene derivative is referred to as fullerene derivative 2.

(Liquid chromatography analysis)
5 mg of a regioisomer mixture of fullerene derivatives was dissolved in 5 mL of toluene (solvent). 5 μL of this solution was injected into liquid chromatography (Alliance 2690, manufactured by Waters). The mobile phase of liquid chromatography was toluene / acetonitrile (55/45, volume ratio), and the flow rate was 1 mL / min. The area percentage value of the mixture of regioisomers of fullerene derivative 2 in the liquid chromatogram obtained by the area percentage method (excluding the solvent toluene) was 59.5%.

Example 4 (Synthesis of fullerene derivative 3)
A regioisomer mixture of fullerene derivatives was synthesized in the same manner as in Example 2 except that the purification conditions using silica gel flash column chromatography were changed to (developing solvent: toluene / ethyl acetate = 1/0 to 95/5). did. This fullerene derivative is referred to as fullerene derivative 3. The area percentage value of the mixture of positional isomers of fullerene derivative 3 in the liquid chromatogram (excluding the solvent toluene) determined by the area percentage method was 82.5%.

フラーレン誘導体４ Example 5 (Synthesis of fullerene derivative 4)
Fullerene _{C 70 (250 mg, 0.30 mmol} ), glycine derivatives 1 (79 mg, 0.45 mmol) and 4-methoxybenzaldehyde (81 mg, 0.60 mmol) and chlorobenzene 50mL was added, and the mixture was heated to reflux for 2 hours. Purification was carried out in the same manner as in Example 1 to obtain 121 mg (0.11 mmol, 37%) of fullerene derivative 4.
¹ H NMR (400 MHz, ppm, CDCl ₃ , J = Hz) δ; ¹³ C NMR (100 MHz, ppm, CDCl ₃ ) δ; IR (Neat, cm ^-1 ) 3443, 2866, 2805, 1609, 1508, 1427, 1032, 1248, 1171, 1131, 1105, 1030, 833, 795, 727, 640, 581, 534; MALDI-TOF-MS (matrix: SA) found 1091.4326 (calcd for C ₈₄ H ₂₁ NO ₃ ⁺ exact Mass : 1091.1521).

Fullerene derivative 4

Example 6 (Production and Evaluation of Organic Thin Film Solar Cell)
An organic thin film solar cell was prepared in the same manner as in Example 2 except that the fullerene derivative 4 was used instead of the fullerene derivative 1, and the photoelectric conversion efficiency was determined. The results are shown in Table 1.

-Evaluation-
As can be seen from Table 1, the positional isomer mixture of fullerene derivative 1 showed higher photoelectric conversion efficiency when used in an organic photoelectric conversion device than [70] PCBM.

Claims (9)

A fullerene derivative represented by the formula (1):

(1)
[In Formula (1), the A ring represents a fullerene skeleton having 70 or more carbon atoms. R ¹ represents a group represented by the following formula (2). R ² is a halogen atom; an aryl group which may have a substituent selected from an alkyl group having 1 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms and a group represented by the following formula (2); An arylalkyl group which may have a group; a monovalent heterocyclic group which may have a substituent and is selected from a pyrrolyl group, a furyl group, a piperidyl group , a quinolyl group and an isoquinolyl group; The group shown by 2) is represented. R ³ represents a hydrogen atom, a halogen atom, an alkyl group, an aryl group which may have a substituent, an arylalkyl group which may have a substituent, or a monovalent which may have a substituent. A heterocyclic group or a group represented by the following formula (2) is represented. ]

(2)
[In Formula (2), m represents an integer of 1 to 6, n represents an integer of 1 to 4, and p represents an integer of 0 to 5. X represents a methyl group or an aryl group which may have a substituent. When there are a plurality of m, the plurality of m may be the same or different. ] R ² is an alkyl group, an alkoxy group and before following formula (2) an aryl group optionally having a substituent selected from the group represented by 1 to 20 carbon atoms having 1 to 20 carbon atoms, R ³ The fullerene derivative according to claim 1, wherein is a hydrogen atom.   The fullerene derivative according to claim 1 or 2, wherein the A ring is a fullerene skeleton having 70 carbon atoms. The method for producing a fullerene derivative according to claim 1, wherein a fullerene having 70 or more carbon atoms, a glycine derivative represented by the formula (3), and an aldehyde compound represented by the formula (4) are reacted.

(3) (4)
(In Formula (3), R ¹ represents a group represented by Formula (2), and R ³ represents a hydrogen atom, a halogen atom, an alkyl group, an aryl group which may have a substituent, or a substituent. Represents an arylalkyl group which may have a monovalent heterocyclic group which may have a substituent or a group represented by the formula (2), wherein R ² is a halogen atom An atom; an aryl group which may have a substituent selected from an alkyl group having 1 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms and a group represented by the formula (2); An arylalkyl group which may have a substituent, a monovalent heterocyclic group selected from a pyrrolyl group, a furyl group, a piperidyl group, a quinolyl group and an isoquinolyl group; or represented by the formula (2) Represents a group.)   A method for purifying a fullerene derivative represented by formula (1), wherein the reaction product obtained by the reaction according to claim 4 is purified by silica gel column chromatography using an aromatic hydrocarbon and an acetate as a developing solvent. Look containing a fullerene derivative and an electron-donating compound according to any one of claims 1 to 3, the ratio of the fullerene derivative, with respect to the electron-donating compound 100 parts by weight, 10 to 1000 parts by weight, Composition for organic photoelectric conversion element . The composition for organic photoelectric conversion elements according to claim 6, wherein the electron donating compound is a polymer compound.   The organic photoelectric conversion element which has a layer containing the fullerene derivative in any one of Claims 1-3.   The organic photoelectric conversion element which has a layer containing the composition of Claim 6 or 7.